Dynamic Power Path Management Simplifies Battery Charging from Solar Panels

Focus:

Originally intended to charge a single-cell Li-ion battery from an ac adapter or USB port, Texas Instruments' bq2403x (bqTINY) linear charge regulators can also be used to charge a Li-ion battery from a solar panel. The advantage in doing so is that the bq2403x contains power path management circuitry that can be used to implement a simple, low-cost form of maximum power point tracking (MPPT). Although not precise, this implementation of MPPT can recover 90% to 95% of the solar panel's energy. In this application report, the author explains the basic operation of a solar cell, the meaning of the maximum power point, and why maximum power point tracking is needed. He then explains how the bq2403x performs dynamic power path management (DPPM) in a typical application and how DPPM can be applied in the solar panel application. A complete schematic is presented for a single-cell Li-ion battery charger that takes power either from a solar panel or a USB port, and takes power to the load from the battery when the other sources are insufficient.

What you’ll learn:

• How to build a low-cost, solar-powered battery charger with maximum power point tracking
• How to build a single-cell Li-ion battery charger that takes power from a solar panel or USB port

Notes:

Application Report SLUA394-October 2006

View the Source

Author & Publication:

Nigel Smith, Texas Instruments, Vendor website, Oct 01 2006

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